From: Randy Lawrence <jm@...>
Date: 2004-07-15T04:33:39+09:00
Subject: Re: How to encode binary for http.post()

Mark Hubbart wrote:

> 
> On Jul 5, 2004, at 2:43 PM, Randy Lawrence wrote:
> 
>> I'm having problems posting a binary string (around 256 characters) 
>> using http.post().
>>
>> When I encode the binary string using Base64.encode64() and then 
>> http.post() the data, the "+" characters are replaced by " " so the 
>> data is no longer valid.
>>
>> I've tried URI.escape(Base64(encode64(data))) to post and 
>> URI.unescape(data) to receive but the same problem appears.
>>
>> Any suggestions?
> 
> 
> The rfc that describes the base64 encoding has a slightly different 
> version of the encoding that is url/filename-safe. It is rather simple 
> to tr the characters around to get the right results:
> 
>   http://www.faqs.org/rfcs/rfc3548.html
> 
> something like this:
> 
>   require 'base64'
>     => nil
>   def Base64.encode64url(str)
>     Base64.encode64(str).tr("+/","-_")
>   end
>     => nil
>   def Base64.decode64url(str)
>     Base64.decode64(str.tr("-_","+/"))
>   end
>     => nil
>   (data = (0..255).inject(""){|a,v|a<<v}).size # all bytes from 0 to 255
>     => 256
>   (encoded = Base64.encode64url(data)).count "+/" # any prohibited 
> characters?
>     => 0
>   # raise error if encoded data is incorrect
>   x=0; Base64.decode(encoded).each_byte{|b| raise if x!=b; x=b+1}; 0
>     => 0
> 
> I wonder if this should be added to the module? In the rfc, it seems to 
> be a standard extension, for use in filenames, urls, etc.
> 
> Additionally, it might be nice to have a base32 implementation shipped. 
> I've coded it myself twice, I recall, and I think it takes all of 20 loc 
> at most.
> 
> cheers,
> Mark
> 
> 
> 

I ran into problems precisely because of this issue.  I had "+" showing 
up as " ".

I simply replace spaces in Base64 encoded string to "+" as a workaround 
but would love something more appropriate/standard to use.